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pbachant October 31, 2013 10:17

pimpleDyMFoam -- lowered viscosity -- time step continuity errors getting large
 
I'm working on some cases with pimpleDyMFoam, which I have gotten to mesh and solve fairly well, but then when I go to drop nu from 1e-6 to 6.7e-7, I am getting time step continuity errors that go up into the 6000 range after a few seconds. This then sets my deltaT so low that the solution effectively halts. Any ideas why this would happen?

Artur November 4, 2013 05:37

My guess would be something happening with either:
Code:

div((nuEff*dev(T(grad(U)))))
or with the turbulent quantities. So either fvSolution or fvSchemes file. Perhaps changing to a lower order scheme, different equation solver, adding underrelaxation or pushing down your tolerances would prevent it from blowing up. It would all depend on how the process actually takes place - showing your log file would help a bit in determining what is actually going on.

Are you using the same mesh for both viscosities? What kind of moving mesh are you using?

All the best,

A


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